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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Um estudo algor?tmico da programa??o da interven??o de sondas de produ??o

Sabry, Gustavo de Araujo 27 February 2012 (has links)
Made available in DSpace on 2014-12-17T15:48:00Z (GMT). No. of bitstreams: 1 GustavoAS_DISSERT.pdf: 3060399 bytes, checksum: 659289bc757f2443a1b6902094747b13 (MD5) Previous issue date: 2012-02-27 / This work approaches the Scheduling Workover Rigs Problem (SWRP) to maintain the wells of an oil field, although difficult to resolve, is extremely important economical, technical and environmental. A mathematical formulation of this problem is presented, where an algorithmic approach was developed. The problem can be considered to find the best scheduling service to the wells by the workover rigs, taking into account the minimization of the composition related to the costs of the workover rigs and the total loss of oil suffered by the wells. This problem is similar to the Vehicle Routing Problem (VRP), which is classified as belonging to the NP-hard class. The goal of this research is to develop an algorithmic approach to solve the SWRP, using the fundamentals of metaheuristics like Memetic Algorithm and GRASP. Instances are generated for the tests to analyze the computational performance of the approaches mentioned above, using data that are close to reality. Thereafter, is performed a comparison of performance and quality of the results obtained by each one of techniques used / O trabalho em quest?o aborda o Problema da Programa??o das Sondas de Produ??o (PPSP) para atender os po?os de um campo de petr?leo. Embora de dif?cil resolu??o, ele ? de extrema import?ncia econ?mica, t?cnica e ambiental. Uma formula??o matem?tica deste problema ? apresentada, assim como desenvolvida uma abordagem algor?tmica. O problema abordado pode ser considerado como o de encontrar o melhor escalonamento de atendimento aos po?os pelas sondas, levando em considera??o a minimiza??o da composi??o dos custos relativos ?s sondas e da perda total da produ??o de petr?leo associada aos po?os que est?o aguardando por atendimento. Tal problema assemelha-se ao Problema de Roteamento de Ve?culos (PRV), que ? classificado como pertencente ? classe de problemas NP-Dif?cil. O objetivo da presente pesquisa ? desenvolver uma abordagem algor?tmica para resolver o PPSP, utilizando os fundamentos de metaheur?sticas como o Algoritmo Mem?tico e o GRASP. Inst?ncias s?o geradas para a realiza??o dos testes computacionais para an?lise do desempenho das abordagens acima citadas, utilizando dados que se aproximam da realidade. A partir da?, ? realizada uma compara??o de desempenho e qualidade dos resultados obtidos por cada uma das t?cnicas utilizadas
22

Busca heur?stica atrav?s de algoritmo gen?tico e mem?tico com constru??o de voc?bulos para o problema de atribui??o de localidades a an?is Sonet

Silva, Ana Cristina Girao e 23 December 2008 (has links)
Made available in DSpace on 2014-12-17T14:52:43Z (GMT). No. of bitstreams: 1 AnaCGS.pdf: 4192359 bytes, checksum: 28eb36354363672f88a28074f9df8b42 (MD5) Previous issue date: 2008-12-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Telecommunications play a key role in contemporary society. However, as new technologies are put into the market, it also grows the demanding for new products and services that depend on the offered infrastructure, making the problems of planning telecommunications networks, despite the advances in technology, increasingly larger and complex. However, many of these problems can be formulated as models of combinatorial optimization, and the use of heuristic algorithms can help solving these issues in the planning phase. In this project it was developed two pure metaheuristic implementations Genetic algorithm (GA) and Memetic Algorithm (MA) plus a third hybrid implementation Memetic Algorithm with Vocabulary Building (MA+VB) for a problem in telecommunications that is known in the literature as Problem SONET Ring Assignment Problem or SRAP. The SRAP arises during the planning stage of the physical network and it consists in the selection of connections between a number of locations (customers) in order to meet a series of restrictions on the lowest possible cost. This problem is NP-hard, so efficient exact algorithms (in polynomial complexity ) are not known and may, indeed, even exist / As telecomunica??es desempenham um papel fundamental na sociedade contempor?nea. Mas ? medida que novas tecnologias s?o introduzidas ao mercado, cresce tamb?m a demanda por novos produtos e servi?os que dependem da infra-estrutura oferecida, tornando os problemas de planejamento de redes de telecomunica??es, apesar da evolu??o tecnol?gica, cada vez maiores e complexos. No entanto, muitos desses problemas podem ser formulados como modelos de otimiza??o combinat?ria, e o uso de algoritmos heur?sticos podem ajudar a solucionar essas quest?es da fase de planejamento. Neste trabalho, foram desenvolvidas duas implementa??es metaheur?sticas puras Algoritmo Gen?tico (AG) e Algoritmo Mem?tico (AM) al?m de uma terceira implementa??o h?brida Algoritmo Mem?tico com Vocabulary Building (AM+VB) para um problema de telecomunica??es que ? conhecido na literatura por Problema de Atribui??o de Localidades a An?is SONET ou SRAP (do ingl?s, SONET Ring Assignment Problem). O SRAP surge durante a etapa do planejamento f?sico da rede e consiste na determina??o das conex?es entre um conjunto de localidades (clientes), de modo a satisfazer uma s?rie de restri??es ao menor custo poss?vel. Esse problema ? NP-dif?cil e portanto algoritmos exatos eficientes (de complexidade polinomial) n?o s?o conhecidos, podendo, inclusive, nem existir
23

Um algoritmo h?brido para o problema de roteamento de ve?culos com frotas heterog?neas

Ferreira, Vanessa Danielle Santos 13 July 2011 (has links)
Made available in DSpace on 2014-12-17T14:53:00Z (GMT). No. of bitstreams: 1 VanessaDSF_DISSERT.pdf: 862759 bytes, checksum: d1e5a8faf841592d593e48b4f4218e61 (MD5) Previous issue date: 2011-07-13 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This paper aims to propose a hybrid meta-heuristics for the Heterogeneous Fleet Vehicle Routing Problem (HVRP), which is a combinatorial optimization problem NP-hard, and is characterized by the use of a limited fleet consists of different vehicles with different capacities. The hybrid method developed makes use of a memetic algorithm associated with the component optimizer Vocabulary Building. The resulting hybrid meta-heuristic was implemented in the programming language C + + and computational experiments generated good results in relation to meta-heuristic applied in isolation, proving the efficiency of the proposed method. / O presente trabalho visa propor uma meta-heur?stica h?brida para o Problema de Roteamento de Ve?culos com Frotas Heterog?neas (PRVFH), que ? um problema de otimiza??o combinat?ria NP-dif?cil, e que se caracteriza pelo uso de uma frota limitada composta por ve?culos distintos com capacidades distintas. O m?todo h?brido desenvolvido utiliza-se de um algoritmo mem?tico associado ao componente otimizador Vocabulary Building. A meta-heur?stica h?brida resultante foi implementada na linguagem de programa??o C++ e os experimentos computacionais geraram bons resultados em rela??o ? meta-heur?stica aplicada isoladamente, comprovando a efici?ncia do m?todo proposto.
24

O problema do caixeiro viajante alugador : um estudo algor?tmico

Silva, Paulo Henrique Asconavieta da 19 December 2011 (has links)
Made available in DSpace on 2014-12-17T15:46:59Z (GMT). No. of bitstreams: 1 PauloHAS_TESE.pdf: 9268945 bytes, checksum: 08c0c5f93ed7b964b99c6df2ee26ab1b (MD5) Previous issue date: 2011-12-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Car Rental Salesman Problem (CaRS) is a variant of the classical Traveling Salesman Problem which was not described in the literature where a tour of visits can be decomposed into contiguous paths that may be performed in different rental cars. The aim is to determine the Hamiltonian cycle that results in a final minimum cost, considering the cost of the route added to the cost of an expected penalty paid for each exchange of vehicles on the route. This penalty is due to the return of the car dropped to the base. This paper introduces the general problem and illustrates some examples, also featuring some of its associated variants. An overview of the complexity of this combinatorial problem is also outlined, to justify their classification in the NPhard class. A database of instances for the problem is presented, describing the methodology of its constitution. The presented problem is also the subject of a study based on experimental algorithmic implementation of six metaheuristic solutions, representing adaptations of the best of state-of-the-art heuristic programming. New neighborhoods, construction procedures, search operators, evolutionary agents, cooperation by multi-pheromone are created for this problem. Furtermore, computational experiments and comparative performance tests are conducted on a sample of 60 instances of the created database, aiming to offer a algorithm with an efficient solution for this problem. These results will illustrate the best performance reached by the transgenetic algorithm in all instances of the dataset / O Problema do Caixeiro Alugador (CaRS) ? uma variante ainda n?o descrita na literatura do cl?ssico Problema do Caixeiro Viajante onde o tradicional tour de visitas do caixeiro pode ser decomposto em caminhos cont?guos e que podem ser realizados em diferentes carros alugados. O problema consiste em determinar o ciclo hamiltoniano que resulte em um custo final m?nimo, considerando o custo da rota adicionado ao custo de uma prov?vel penaliza??o paga em cada troca de ve?culos na rota, penaliza??o devida ao retorno do carro descartado at? a sua cidade base. Sem perda para a generalidade do caso, os custos do aluguel do carro podem ser considerados embutidos nos custos da rota do carro. O presente trabalho introduz o problema geral e o exemplifica, caracterizando igualmente algumas variantes associadas. Uma an?lise geral da complexidade desse problema combinat?rio ? descrita, visando justificar sua classifica??o na classe NP-dif?cil. Um banco de inst?ncias para o problema ? apresentado, descrevendo-se a metodologia de sua constitui??o. O problema proposto tamb?m ? objeto de um estudo algor?tmico experimental baseado na aplica??o de seis metaheur?sticas de solu??o, representando adapta??es do melhor do estado da arte em programa??o heur?stica. Novas vizinhan?as, procedimentos construtivos, operadores de busca, agentes evolucion?rios, coopera??o por multiferom?nios, s?o criados para o caso. Experimentos computacionais comparativos e testes de desempenho s?o realizados sobre uma amostra de 60 inst?ncias, visando oferecer um algoritmo de solu??o competitivo para o problema. Conclui-se pela vantagem do algoritmo transgen?tico em todos os conjuntos de inst?ncias
25

O problema do caixeiro alugador com coleta de bonus: um estudo algoritmico / Prize Collecting Traveling Car Renter Problem: an Algotithm Study

Menezes, Matheus da Silva 21 March 2014 (has links)
Made available in DSpace on 2015-03-03T15:48:41Z (GMT). No. of bitstreams: 1 MatheusSM_TESE.pdf: 3657538 bytes, checksum: 05bf71663b044728a1e70b6db57b834e (MD5) Previous issue date: 2014-03-21 / This paper introduces a new variant of the Traveling Car Renter Problem, named Prizecollecting Traveling Car Renter Problem. In this problem, a set of vertices, each associated with a bonus, and a set of vehicles are given. The objective is to determine a cycle that visits some vertices collecting, at least, a pre-defined bonus, and minimizing the cost of the tour that can be traveled with different vehicles. A mathematical formulation is presented and implemented in a solver to produce results for sixty-two instances. The proposed problem is also subject of an experimental study based on the algorithmic application of four metaheuristics representing the best adaptations of the state of the art of the heuristic programming.We also provide new local search operators which exploit the neighborhoods of the problem, construction procedures and adjustments, created specifically for the addressed problem. Comparative computational experiments and performance tests are performed on a sample of 80 instances, aiming to offer a competitive algorithm to the problem. We conclude that memetic algorithms, computational transgenetic and a hybrid evolutive algorithm are competitive in tests performed / Este trabalho apresenta uma nova variante do problema do Caixeiro Alugador ainda n?o descrita na literatura, denominada de Caixeiro Alugador com Coleta de Pr?mios. Neste problema s?o disponibilizados um conjunto de v?rtices, cada um com um b?nus associado e um conjunto de ve?culos. O objetivo do problema ? determinar um ciclo que visite alguns v?rtices coletando, pelo menos, um b?nus pr?-de nido e minimizando os custos de viagem atrav?s da rota, que pode ser feita com ve?culos de diferentes tipos. ? apresentada uma formula??o matem?tica e implementada em um solver produzindo resultados em sessenta e duas inst?ncias. O problema proposto tamb?m ? objeto de um estudo algor?tmico experimental baseado na aplica??o de quatro metaheur?sticas de solu??o, representando adapta??es do melhor do estado da arte em programa??o heur?stica. Nesse trabalho tamb?m apresentamos a constitui??o de novos operadores que exploram as vizinhan?as do problema, procedimentos construtivos e adapta??es, criados especifi camente para o problema abordado. Experimentos computacionais comparativos e testes de desempenho s?o realizados sobre uma amostra de 80 inst?ncias, visando oferecer um algoritmo de solu??o competitivo para o problema. Conclui-se que algoritmos com abordagem mem?tica, transgen ?tica e evolucion?ria h?brida obtiveram resultados competitivos nos testes efetuados. Palavras-chave: Caixeiro Alugador com Coleta de Pr?mios. Metaheur?sticas. GRASP/VNS. Algoritmo Mem?tico. Transgen?tica Computacional. Computa??o Evolucion?ria
26

Le problème de job-shop avec transport : modélisation et optimisation / Job-shop with transport : its modelling and optimisation

Larabi, Mohand 15 December 2010 (has links)
Dans cette thèse nous nous sommes intéressés à l’extension du problème job-shop en ajoutant la contrainte du transport des jobs entre les différentes machines. Dans cette étude nous avons retenu l’existence de deux types de robots, les robots de capacité de chargement unitaire (capacité=1 veut dire qu’un robot ne peut transporter qu’un seul job à la fois) et les robots de capacité de chargement non unitaire (capacité>1 veut dire qu’un robot peut transporter plusieurs job à la fois). Nous avons traité cette extension en deux étapes. Ainsi, la première étape est consacrée au problème du job-shop avec plusieurs robots de capacité de chargement unitaire et en seconde étape en ajoutant la capacité de chargement non unitaire aux robots. Pour les deux problèmes étudiés nous avons proposé :• Une modélisation linéaire ;• Une modélisation sous forme de graphe disjonctif ;• Plusieurs heuristiques de construction de solutions ;• Plusieurs recherches locales qui améliorent les solutions obtenues ;• Utilisation des algorithmes génétiques / mémétiques comme schéma global d’optimisation ;• De nouveaux benchmarks, des résultats de test de nos approches sur nos benchmarks et ceux de la littérature et ces résultats sont commentés et comparés à ceux de la littérature. Les résultats obtenus montrent la pertinence de notre modélisation ainsi que sa qualité. / In this thesis we are interested in the extension of the job-shop problem by adding the constraint of transport of jobs between different machines. In this study we used two types of robots, robots with unary loading capacity (capacity =1 means that each robot can carry only one job at a time,) and robots with non unary loading capacities (robot with capacity >1 can carry more than one job at time). Thus, the first step is devoted to the problem of job-shop with several robots with unary loading capacity. In the second step we extend the problem by adding the non-unary loading capacities to the robots. For both problems studied we have proposed :• A linear modeling ;• A Disjunctive graph Model ;• Several constructive heuristics ;• Several local searches methods that improve the obtained solutions ;• Use of genetic / memetic algorithms as a global optimization schema ;• New benchmarks, test results of our approaches on our benchmarks and those present in the literature and these results are commented and compared with those of literature. The results show the relevance of our model and its quality.

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